The present invention relates generally to a method and device for delivering a radioactive dose and/or drugs alone or in combination with the deployment of a stent.
Various types of brachytherapy treatments employ radioactive material, such as treatments designed to combat cancer or to prevent scar issue build-up. One manner of brachytherapy involves inserting devices comprising radioactive materials into a body (e.g., a human body) to provide localized irradiation.
Once such use of radioactive materials is to prevent restenosis in a blood vessel. Intra-vascular stents have been used to prevent restenosis after angioplasty procedures. Intra-vascular stents may suffer from the drawback of excessive scar tissue growth (e.g., intimal hyperplasia) at the site of the angioplasty and/or the stent due to trauma to the vessel which results from a combination of the angioplasty and stenting procedures, thereby reducing the long-term effectiveness of the procedure.
One attempt to solve this problem has been to incorporate radioactive material into a stent, thereby irradiating vessel tissue at the stent site to reduce tissue growth at the site. Such stents, however, may be difficult and costly to manufacture. Incorporating radioactive material in such a stent may for example, require coating the stent with a layer of radioactive material and binding the radioactive material to the stent. Coating the stent may be difficult due to the stent structure, since many stents have a helical or other complex geometric structure in order to provide support to the vessel without occluding flow through the vessel.
Additionally, radioactive stents may use a sealing layer to adhere the radioactive material to the stent, and/or to provide the stent with certain physical properties desirable for a stent (e.g., coil spring stents). A sealing layer may reduce the effective dose of radioactivity by blocking or absorbing a portion of the radioactivity. This may require use of larger amounts of costly radioactive material. Further, sealing layers may have an adverse impact on the uniformity of the radiation dosage delivered by the stents. For example, unless such sealing layers are uniform, thicker areas of the sealing layer may reduce the dosage delivered by the radioactive material more than thinner areas of the sealing layer, thereby resulting in a non-uniform dosage.
When using radioactive material to treat tissue, it important for the radioactive material to be as close to the tissue as possible, thereby allowing the minimum amount of radioactive material to be used, to provide an effective dose and to minimize the dosage delivered to other tissues. Using sealing layers or other coatings to attach the radioactive material to the stent results in the radioactive material being placed further away from the vessel than desired.
These and other drawbacks exist.
An object of certain embodiments of the present invention is to overcome these and other drawbacks in existing systems and methods.
Another object of certain embodiments of the invention is to provide a device for use in connection with a vascular stent to radiate and/or deliver drugs to a localized area in a vessel in a body.
Another object of certain embodiments of the invention is to provide a device for implantation in vessel to irradiate and/or deliver drugs to a localized area.
Additional objects and advantages of the invention will be set forth in part in the description, or may be learned by practice of the invention.
To achieve these objects and in accordance with the purpose of the invention, as embodied and broadly described herein, the present invention provides, in one embodiment, a foil sheet comprising a radioactive material useful in association with a stent for delivery of a localized radiation dosage.
In another embodiment, the present invention relates to the combination of a stent and a foil sheet comprising a radioactive material. The stent and foil sheet are positioned so that the radioactive material in the foil sheet can deliver a localized radiation dosage to a prescribed area.
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an embodiment of the invention and, together with the description, serve to explain the principles of the invention, but in no way constitute the entire invention and are not to be construed as limits the invention in any way.